MRI: Acquisition of an Atmospheric Pressure Ionization Mass Spectrometer for Measurements of Trace Gases and Secondary Organic Aerosol Components in Air

加州大学欧文分校的Barbara Finlayson-Pitts教授和他的同事Michael Kleinman、Sergey Nizkorodv、Donald Blake和Eric Saltzman获得了化学专业研究仪器计划颁发的这一奖项，他们将获得一台能够对气体和颗粒进行高灵敏度和特定测量的大气压QTrap质谱仪。该仪器能够利用纳解吸电喷雾电离(Nano-DESI)、萃取式电喷雾电离(EESI)、大气固体分析探头(ASAP)电离和大气压电离(API)进行二次有机气溶胶(SOA)的分子分析。该建议旨在加强各级的研究和教育，特别是在下列领域：(A)异戊二烯光氧化产物的测定以及相对湿度对气溶胶成分的影响；(B)实时测量复杂的挥发性有机化合物(VOCs)-二氧化氮-臭氧混合物中形成的SOA颗粒的组成；(C)通过与傅立叶变换红外(FTIR)测量相比较，阐明气溶胶质谱仪(AMS)测量有机硝酸盐的效率；(D)测量烟草烟雾中的VOCs；(E)测量异戊二烯光氧化产生的含氮VOCs；(F)测定水相酸和醛的光化学氧化产物；(G)实时测量新颗粒形成和生长期间气溶胶流动管中的气体前体和产物；(H)实时测量α-品烯与臭氧、氢氧化物和硝酸盐反应产生的气态对伞花烃；(I)测量超氧化物歧化酶的氧/碳比，并与高分辨率电喷雾电离质谱仪的结果进行比较；(I)作为北大西洋气体流量研究和其他研究活动一部分的巡航期间丙酮和其他含氧有机物种的实时测量。质谱学(MS)是用于识别和表征嵌入复杂基质中的少量化学物种的关键分析方法之一。在一个典型的实验中，这些组分流入质谱仪，在那里它们被电离成母离子，并测量它的碎片离子及其质量。这种高度灵敏的技术可以检测和确定复杂混合物中的分子结构。具有串联能力的仪器通过进一步碎裂光谱仪中产生的离子来提供额外的结构识别能力。该奖项提供的仪器将为几个系的教职员工和学生提供利用该机构迄今尚未提供的现代仪器进行研究项目的机会。这项研究不仅将对化学领域产生影响，还将提供有关大气现象的重要知识。该仪器还将用于几门实验室课程，以培训大量学生使用这一重要的分析技术。

With this award from the Chemistry Major Research Instrumentation Program, Professor Barbara Finlayson-Pitts from University of California Irvine and colleagues Michael Kleinman, Sergey Nizkorodov, Donald Blake and Eric Saltzman will acquire an atmospheric pressure QTrap mass spectrometer that is capable of highly sensitive and specific measurements of both gases and particles. The instrument is capable of carrying out tandem experiments involving molecular analysis of secondary organic aerosols (SOA) using nano-desorption electrospray ionization (nano-DESI), extractive electrospray ionization (EESI), atmospheric solids analysis probe (ASAP) ionization and atmospheric pressure ionization (API). The proposal is aimed at enhancing research and education at all levels, especially in areas such as (a) determination of the products of isoprene photooxidation and the effects of relative humidity on the aerosol composition; (b) real-time measurements of the composition of SOA particles formed in complex volatile organic compounds (VOCs)-nitrogen dioxide-ozone mixtures; (c) elucidation of the efficiency of aerosol mass spectrometry (AMS) for measurements of organic nitrates by comparison to Fourier Transform infrared (FTIR) measurements; (d) measurement of VOCs in tobacco smoke; (e) measurement of nitrogen-containing VOCs from isoprene photooxidation; (f) determination of products of photochemical oxidations of aqueous phase acids and aldehydes; (g) real-time measurement of gaseous precursors and products in an aerosol flow tube during new particle formation and growth; (h) real-time measurement of gaseous p-cymene from the reaction of alpha-pinene with ozone, OH, and nitrate; (i) measurement of oxygen/carbon ratios of SOA and comparison to results from high-resolution electrospray ionization mass spectrometry; (i) real-time measurements of acetone and other oxygenated organic species during a cruise that is part of a North Atlantic gas flux study as well as other research activities.Mass Spectrometry (MS) is one of the key analytical methods used to identify and characterize small quantities of chemical species embedded in complex matrices. In a typical experiment, the components flow into a mass spectrometer where they are ionized into the parent ion and its fragment ions and their masses are measured. This highly sensitive technique allows detection and determination of the structure of molecules in a complex mixture. An instrument with tandem capability provides additional structural identification power through further fragmentation of ions produced in the spectrometer. The instrumentation provided by this award will provide faculty and students in several departments the opportunity to pursue research projects using modern instrumentation not heretofore available at the institution. The research will impact not only the field of Chemistry but also provide important knowledge of atmospheric phenomena. The instrument will also be used in several laboratory courses to train significant numbers of students in the use of this important analytical technique.